Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: [PATCH 07/20] blkio: Provide capablity to enqueue/dequeue group entities | Date | Wed, 04 Nov 2009 10:34:57 -0500 |
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Vivek Goyal <vgoyal@redhat.com> writes:
> o This patch embeds cfq_entity object in cfq_group and provides helper routines > so that group entities can be scheduled. > > Signed-off-by: Vivek Goyal <vgoyal@redhat.com> > --- > block/cfq-iosched.c | 110 +++++++++++++++++++++++++++++++++++++++++++-------- > 1 files changed, 93 insertions(+), 17 deletions(-) > > diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c > index bc99163..8ec8a82 100644 > --- a/block/cfq-iosched.c > +++ b/block/cfq-iosched.c > @@ -79,6 +79,7 @@ struct cfq_service_tree { > #define CFQ_RB_ROOT (struct cfq_service_tree) { RB_ROOT, NULL, 0, NULL} > > struct cfq_sched_data { > + unsigned int nr_active; > struct cfq_service_tree service_tree[IO_IOPRIO_CLASSES]; > }; > > @@ -89,6 +90,10 @@ struct cfq_entity { > struct cfq_service_tree *st; > unsigned short ioprio_class; > bool ioprio_class_changed; > + struct cfq_entity *parent; > + bool on_st; > + /* Points to the sched_data of group entity. Null for cfqq */ > + struct cfq_sched_data *my_sd;
Why my_sd? None of the other members required a my. ;-)
> +static inline struct cfq_entity *parent_entity(struct cfq_entity *cfqe) > +{ > + return cfqe->parent; > +}
Wow, is this really necessary for a pointer dereference?
> +#ifdef CONFIG_CFQ_GROUP_IOSCHED > +/* check for entity->parent so that loop is not executed for root entity. */ > +#define for_each_entity(entity) \ > + for (; entity && entity->parent; entity = entity->parent)
See, you don't use it here!
> @@ -660,7 +723,13 @@ static void enqueue_cfqe(struct cfq_entity *cfqe) > > static void enqueue_cfqq(struct cfq_queue *cfqq) > { > - enqueue_cfqe(&cfqq->entity); > + struct cfq_entity *cfqe = &cfqq->entity; > + > + for_each_entity(cfqe) { > + if (cfqe->on_st) > + break; > + enqueue_cfqe(cfqe); > + } > }
Maybe I'm slow, but I would have benefitted from a comment above that function stating that we have to walk up the tree to make sure that the parent is also scheduled.
Cheers, Jeff
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